Field of the Invention
The present invention relates to an image forming system, an image forming apparatus, and a post processing apparatus, and more particularly, to a control method of conveying recording material to the post processing apparatus after the recording material is subjected to image formation by the image forming apparatus in response to image formation instructions from outside the apparatus.
Description of the Related Art
A conventional image forming apparatus performs image formation on recording material according to image formation instructions (print request signal) from an external device such as a host computer and then discharges the recording material with an image formed thereon through a discharge port provided as standard in the image forming apparatus. When a relatively large quantity of recording material is handled, an image forming apparatus connected with a post processing apparatus on a discharge side of the image forming apparatus has been proposed, the post processing apparatus being equipped with a post processing unit adapted to perform post processing operations such as sorting and stapling of the recording material. With such an image forming apparatus, it is necessary to control conveyance intervals of recording material by taking into consideration the time required for the post processing operations of the post processing apparatus according to the type of recording material and the conveyance speed of the recording material. For example, Japanese Patent Application Laid-Open No. 2008-214103 proposes the following configuration. That is, with the proposed configuration, at the time of reservation for sheet discharge, a controller notifies a control unit of a sheet discharge apparatus about the type of recording material to be discharged and the controller acquires a conveyance interval time according to the type of recording material from the control unit of the sheet discharge apparatus.
However, the conventional post processing apparatus has the following problem. Due to the need to solve temperature risings on non-paper passing areas of a fixing apparatus or depending on a detection result of recording material type, some image forming apparatuses do printing under printing conditions differing in the recording material type and the conveyance speed of the recording material from those, of which the post processing apparatus is notified at the time of sheet discharge reservation. If a post processing apparatus is connected to such an image forming apparatus, it is necessary that the post processing apparatus notify the image forming apparatus of the conveyance interval time based on the most time-consuming process of the post processing apparatus without regard to the type of recording material and the conveyance speed of the recording material specified at the time of sheet discharge reservation. Consequently, the conveyance interval time, of which the engine control unit is notified by the controller becomes longer than necessary, which may result in reduced productivity of the image forming apparatus.